Q: Charge dropped too fast

[Yesim-Mike]

We had our FFE fully charged and when we were leaving the range was 101 miles. We drove 2.8 miles, so when we parked it said we had 98 miles to go. However, when we got in the car an hour later, the range was down to 78 miles. How can we lose 20 miles just like that? Any ideas?

 

[jmueller065]

Keep in mind that the stated "Range" is just a guess by the car. If you really want to see if you are losing charge: On the entertainment display (My Ford Touch screen in the center council) press the button on the bottom right that looks like leaves. On the right in that screen it will show a % state of charge--that is your current battery level.

That range meter is frequently referred as the "Guess-O-Meter":
http://jamiegeek.myevblog.com/2013/10/12/the-guess-o-meter/

 

[Yesim-Mike]

Guess-O-Meter The last line in the blog is exactly what happened to us

 

[WattsUp]

We had our FFE fully charged and when we were leaving the range was 101 miles. We drove 2.8 miles, so when we parked it said we had 98 miles to go. However, when we got in the car an hour later, the range was down to 78 miles. How can we lose 20 miles just like that? Any ideas?

Normally, I don't see the car report drastically different range estimates between turning off and turning on the next time.

But... did you do something different, like turn on the climate controls when you started the car for the second time? With a 98 mile estimate, turning on any climate (A/C or heat) is likely to clobber the estimate.

Maybe you had the climate on "Auto" and, when you started the car the second time, it turned on A/C or heat automatically (which was not on at the time when you last turned the car off). That could change the estimate.

 

[Abelgoddard]

I just want to know how you start off with a guesstimated range of 101 from a full charge, when the full charge is 78? Am I the only one questioning that part?

 

[michael]

It looks at your recent energy efficiency and guesses based on that. For example, if you came down a big hill on your way home and then charged up, it would think you were going to keep driving at a very low power consumption.

My daughter got in a jam exactly that way. I came down a hill and arrived home with maybe 15% of the battery left, but it said it was good for 30 miles so she took to the car out and barely, barely made it home.

 

[jmueller065]

I just want to know how you start off with a guesstimated range of 101 from a full charge, when the full charge is 78? Am I the only one questioning that part?

Yes: if your previous drive was very efficient then a full charge can show 100+ miles of range. A full charge is 100% battery, not a specific number of miles--which is why its called the "Guess-O-Meter" (in my blog post I linked to above I have an example where the GOM shows 200+ miles).

In the summer months I frequently see 100 miles of range showing on a full charge.

 

[hybridbear]

The car will also personalize the range estimate based on which key is driving and the history of driving efficiency for that key. My parents will see different range estimates with each key in their Energi since one of them drives more efficiently.

 

[davideos]

Don't count on the range. Rely on the percentage of charge. After driving the FFE for some time, you will be familiar with the limits.

As for the drastic reduction, all the theories mentioned seem valid possibilities, but I will add that the algorithm definitely looks at the last trip made. If it said you will get 101, then the trip before was likely downhill. Also, if your state of charge is low and you are going downhill, you can see large swings in the reported range. It seems to me that it takes a weighted average. Depending on your state of charge the weighting algorithm applied was different from when you last drove to when you turned it on next.

Anyway, although everyone calls it a "guess-o-meter", it is usually more consistent if your driving is consistent. But as you get familiar with the car's range in your environment, you won't worry so much about what the range says...it is doing what it was programmed to do...take all the data at its disposal and make a prediction based on trend.

 

[Yesim-Mike]

I just want to know how you start off with a guesstimated range of 101 from a full charge, when the full charge is 78? Am I the only one questioning that part?

Yes: if your previous drive was very efficient then a full charge can show 100+ miles of range. A full charge is 100% battery, not a specific number of miles--which is why its called the "Guess-O-Meter" (in my blog post I linked to above I have an example where the GOM shows 200+ miles).

In the summer months I frequently see 100 miles of range showing on a full charge.

My husband has been doing much better than me, so probably that is why he saw 101 miles. BTW, we conditioned the car before we unplugged it and didn't turn the AC on in our short trip. However, the weather being hot may made the car use energy to cool off the battery and when we turned it on again, it may have made the adjustment. BTW, I had the last My View setting given at this blog http://jamiegeek.myevblog.com/2013/09/25/butterflies-really-what-your-dashboard-can-tell-you/

 

[Yesim-Mike]

Don't count on the range. Rely on the percentage of charge. After driving the FFE for some time, you will be familiar with the limits.

As for the drastic reduction, all the theories mentioned seem valid possibilities, but I will add that the algorithm definitely looks at the last trip made. If it said you will get 101, then the trip before was likely downhill. Also, if your state of charge is low and you are going downhill, you can see large swings in the reported range. It seems to me that it takes a weighted average. Depending on your state of charge the weighting algorithm applied was different from when you last drove to when you turned it on next.

Anyway, although everyone calls it a "guess-o-meter", it is usually more consistent if your driving is consistent. But as you get familiar with the car's range in your environment, you won't worry so much about what the range says...it is doing what it was programmed to do...take all the data at its disposal and make a prediction based on trend.

Well said, thanks! I wonder the effect of the outside temperature on these calculations. I doubt this will be in the model, but real time traffic data, i.e. if there is a big traffic jam on a highway passed beyond an exit where you can get off...

 

[hybridbear]

Don't count on the range. Rely on the percentage of charge. After driving the FFE for some time, you will be familiar with the limits.

As for the drastic reduction, all the theories mentioned seem valid possibilities, but I will add that the algorithm definitely looks at the last trip made. If it said you will get 101, then the trip before was likely downhill. Also, if your state of charge is low and you are going downhill, you can see large swings in the reported range. It seems to me that it takes a weighted average. Depending on your state of charge the weighting algorithm applied was different from when you last drove to when you turned it on next.

Anyway, although everyone calls it a "guess-o-meter", it is usually more consistent if your driving is consistent. But as you get familiar with the car's range in your environment, you won't worry so much about what the range says...it is doing what it was programmed to do...take all the data at its disposal and make a prediction based on trend.

Well said, thanks! I wonder the effect of the outside temperature on these calculations. I doubt this will be in the model, but real time traffic data, i.e. if there is a big traffic jam on a highway passed beyond an exit where you can get off...

Check out the survey in another section of the forum. One of the questions is about if EV owners would have an appetite for range calculations that include such factors.